Question

Let A and B be two sets in the same universal set. Then A - B is a null set if

• A. A and B are disjoint sets
• B. A is contained in B
• C. B is contained in A
• D. A and B are both Null Sets

Answer 1

Answer: (B), (D)

The correct options are
B A is contained in B
D A and B are both Null Sets

If A is contained in B then A - B is a null set because all the elements of set A belongs to set B.

If A and B are null sets, then A - B is also a null set.